MSTOHZ(9) | Kernel Developer's Manual | MSTOHZ(9)

# NAME

mstohz, hztoms — convert between milliseconds and system clock ticks

# SYNOPSIS

#include <sys/param.h>

int
mstohz(int ms);

int
hztoms(int hz);

# DESCRIPTION

The mstohz() macro can be used to convert time in milliseconds to system clock ticks, as used by the callout(9) facility, in an integer-overflow safe way. Conversely, hztoms() converts system clock ticks to milliseconds.

These macros are defined in the <sys/param.h> header. Individual ports can have a processor-specific, more efficient version implemented in their <machine/param.h> header as a define.

# RETURN VALUES

The return value is either the number of clock ticks or milliseconds for the specified value.

# SEE ALSO

param(3), callout(9), tvtohz(9)

# BUGS

Neither mstohz() nor hztoms() make use of expensive 64-bit integer arithmetic. The result from mstohz() will be rounded down to one second if the parameter is larger than 131072 milliseconds.

October 20, 2011 | NetBSD 7.2